The Sunderland boss is threatening to make big changes to his squad after becoming the victims of another cup shock and dismayed at their inconsistency.

After setting a "benchmark" good performance in beating West Ham last weekend, this was close to a new low for O'Neill.

Sordell stepped up to convert in the 64th minute penalty for his third goal of the season, then added a second to seal the victory with a simple prod home from six yards out 10 minutes later.

Dougie Freedman's Championship visitors matched their Premier League rivals throughout the match and deserved their moment. But Sunderland fans will be infuriated at seeing such a meek surrender.

O'Neill has spent the build-up to this season's Cup games saying they are right at the top of the club's list of priorities - because it is the only thing that can bring glory and excitement.

But that billing was totally at odds with this capitulation - Bolton out-passed Sunderland and desired the win more.

O'Neill said: "If we can't do it with our present team... this is it. This is a big club. We should not be spending 40 years without winning something, we really shouldn't.

"People have come to the game, put their hands in their pocket to watch us. We have to galvanise ourselves, show consistency and run four or five games, putting everything into the game. I think we should demand this.

"It is a disappointing to go out of the competition. We have gone out too meekly for my liking - especially after playing so well on Saturday.

"We put in a big effort to come back in the first game to get a replay and we have thrown it away.

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Keep it tight: Eagles is challenged by Sunderland player Jack Colback

"We did not take our chances in the first half or create enough in the second half. I think the penalty was rather dubious and Jack says he got the first touch on the ball and that is a big moment.

"But Bolton put in a big effort and we are disappointed. Steven Fletcher was a big miss, he was ill. I am hoping he'll be ok for Saturday. But we should be able to cope. The whole idea of a squad to to cope with these things.

"It is 40 years since this club won a trophy and that is far too long. Now we are out in the third round. Galling.

"I am disappointed. Other people play weakened sides, but we have tried to win and we have not been able to."

Sordell, a talented handful, spent the first half getting into decent positions but failing to exploit his chances.

But he stepped up a level after the break and got his penalty chance when Darren Pratley drew a foul from Jack Colback. Ref Kevin Friend got the decision right and Sordell dispatched the spot-kick with ease.

The England U21 international was then on hand to stab home the second, out-muscling Matthew Kilgallon, who failed to clear over-lapping full-back Tyrone Mears' cross after Chris Eagles' prompting had opened up the defence.

Sordell has now scored four this season - three of them against Sunderland.

It meant for the second time this season the Wearsiders have blown a cup chance against lower league opposition, despite O'Neill's insistence that he makes the cups his top priority.

They also collapsed against neighbours Boro in the Capital One Cup in October.

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At the double: Sordell celebrates scoring his second of the night

Sunderland now have just Premier League survival to play for - a major blow to O'Neill who wants to make some sort of history in the next couple of seasons in charge.

But this defeat reinforced the manager's point that, just because they beat West Ham 3-0 on Saturday, they have not suddenly turned into a great side.

He may use the evidence of last night's performance to bargain for an over haul of his pedestrian looking squad.

Delighted Freedman, whose Trotters are now at home to Everton in round four, said: "We had a game-plan that we stuck to. We defended well, stuck in our holes and limited Sunderland. We grew into the game with our passing and that got us the win.

"Over the 90 minutes, we deserved to win.

"We knew we had to hang in there for an hour. I felt that in the last half hour we could have the energy to attack them.

"Marvin has done well and there is pressure on the young lad. I stripped him down and got back to basics with him and we have to get him being a goal scorer.

"Our back six deserve credit too. We are looking forward to a tie against Everton. We can perform against anyone if we defend like that and express ourselves going forward."